Energy Storage to Balance Wind Power Fluctuations

Keywords

Abstract

Over the last 15 years wind energy becomes more and
more important in Germany. The total installed capacity
of wind generation was 19300 MW (June 2006) with new
installation of about 900 MW in the first 3 month in 2006.
In 2010 the contribution of renewable energy to the gross
electricity consumption shall be 12.5 per cent (renewable
energy sources act EEG) and in 2020 20 per cent. The
acceptance of utilisation of wind power in Germany is
very high. Wind energy supply varies over day time, over
the year and regional. In addition demand of electrical
power varies over daytime and over the year but not
correlated with the variation of wind. The average full
load hours of the German wind generation is about
1600 h/a and will increase 2010 to about 1960 h/a based
on increasing off-shore wind parks in Germany. In 2010
24 GW wind plants are planned on-shore, in the North
Sea additional 4.4 GW off-shore wind parks and in the
Baltic Sea about 1 GW off-shore wind generation. This
will increase 2015 to 8.4 GW (North Sea) and 1.4 GW
(Baltic Sea).
The load centers in Germany are in the central and
southern parts of Germany far away from the main wind
park locations at the coasts or off-shore. To transport this
high power to the load centers some hundred kilometre of
new AC and DC lines have to be built together with new
compensation and control equipment to strengthen and
operate the system securely. 4 main corridors each with a
capacity of 2000-4000 MW are necessary to bring the
power to the load centers. In the last years there is a
discussion about the necessity of such a large
improvement of the system and the possibilities to solve
the transportation targets closer related to the average
available wind power and not related to the size of
installed wind power capacity. A possible alternative is
the installation of energy storage systems based on
compressed air (so called compressed air energy storage
CAES) stored in large underground caverns. The paper
will show the available technology and the possibilities to
combine these storage equipment with wind parks to use
wind parks in a way of quasi conventional power plants.